org.springframework.boot.actuate.endpoint.annotation.ReadOperation#io.github.resilience4j.circuitbreaker.CircuitBreaker源码实例Demo

@Test
public void shouldNotBufferEvents() {
    CircuitBreaker circuitBreaker = CircuitBreaker.ofDefaults("testName");
    CircularEventConsumer<CircuitBreakerEvent> ringBuffer = new CircularEventConsumer<>(2);
    assertThat(ringBuffer.getBufferedEvents()).isEmpty();

    circuitBreaker.onError(0, TimeUnit.NANOSECONDS, new RuntimeException("Bla"));
    circuitBreaker.onError(0, TimeUnit.NANOSECONDS, new RuntimeException("Bla"));
    circuitBreaker.onError(0, TimeUnit.NANOSECONDS, new RuntimeException("Bla"));
    //Subscription is too late
    circuitBreaker.getEventPublisher().onEvent(ringBuffer);

    CircuitBreaker.Metrics metrics = circuitBreaker.getMetrics();
    assertThat(metrics.getNumberOfBufferedCalls()).isEqualTo(3);
    assertThat(metrics.getNumberOfFailedCalls()).isEqualTo(3);
    //Because Subscription was too late
    assertThat(ringBuffer.getBufferedEvents()).hasSize(0);
}
 

@Test
public void decorateUnsuccessfulCall() throws Exception {
    stubFor(get(urlPathEqualTo("/greeting"))
        .willReturn(aResponse()
            .withStatus(500)
            .withHeader("Content-Type", "text/plain")));

    final Response<String> response = service.greeting().execute();

    assertThat(response.code())
        .describedAs("Response code")
        .isEqualTo(500);

    final CircuitBreaker.Metrics metrics = circuitBreaker.getMetrics();
    assertThat(metrics.getNumberOfFailedCalls()).isEqualTo(1);
}
 

@Before
public void init() {
    TimeLimiterConfig timeLimiterConfig = TimeLimiterConfig.custom()
            .timeoutDuration(Duration.ofSeconds(1))
            .cancelRunningFuture(true)
            .build();
     timeLimiter = TimeLimiter.of(timeLimiterConfig);

    CustomizableThreadFactory factory = new CustomizableThreadFactory("timeLimiter-");
    factory.setDaemon(true);
    executorService = Executors.newCachedThreadPool(factory);

    CircuitBreakerConfig circuitBreakerConfig = CircuitBreakerConfig
            .custom()
            .enableAutomaticTransitionFromOpenToHalfOpen()
            .failureRateThreshold(50)
            .ringBufferSizeInClosedState(10)
            .ringBufferSizeInHalfOpenState(2)
            .build();

    circuitBreaker = CircuitBreaker.of("backendName", circuitBreakerConfig);
}
 

@Test
public void shouldCreateCircuitBreakerRegistryWithRegistryStore() {
    RegistryEventConsumer<CircuitBreaker> registryEventConsumer = getNoOpsRegistryEventConsumer();
    List<RegistryEventConsumer<CircuitBreaker>> registryEventConsumers = new ArrayList<>();
    registryEventConsumers.add(registryEventConsumer);
    Map<String, CircuitBreakerConfig> configs = new HashMap<>();
    final CircuitBreakerConfig defaultConfig = CircuitBreakerConfig.ofDefaults();
    configs.put("default", defaultConfig);
    final InMemoryCircuitBreakerRegistry inMemoryCircuitBreakerRegistry =
        new InMemoryCircuitBreakerRegistry(configs, registryEventConsumers,
            io.vavr.collection.HashMap.of("Tag1", "Tag1Value"), new InMemoryRegistryStore());

    assertThat(inMemoryCircuitBreakerRegistry).isNotNull();
    assertThat(inMemoryCircuitBreakerRegistry.getDefaultConfig()).isEqualTo(defaultConfig);
    assertThat(inMemoryCircuitBreakerRegistry.getConfiguration("testNotFound")).isEmpty();
    inMemoryCircuitBreakerRegistry.addConfiguration("testConfig", defaultConfig);
    assertThat(inMemoryCircuitBreakerRegistry.getConfiguration("testConfig")).isNotNull();
}
 

@Override
public <T> Mono<T> run(Mono<T> toRun, Function<Throwable, Mono<T>> fallback) {
	io.github.resilience4j.circuitbreaker.CircuitBreaker defaultCircuitBreaker = registry
			.circuitBreaker(id, config.getCircuitBreakerConfig());
	circuitBreakerCustomizer
			.ifPresent(customizer -> customizer.customize(defaultCircuitBreaker));
	Mono<T> toReturn = toRun
			.transform(CircuitBreakerOperator.of(defaultCircuitBreaker))
			.timeout(config.getTimeLimiterConfig().getTimeoutDuration())
			// Since we are using the Mono timeout we need to tell the circuit breaker
			// about the error
			.doOnError(TimeoutException.class,
					t -> defaultCircuitBreaker.onError(config.getTimeLimiterConfig()
							.getTimeoutDuration().toMillis(), TimeUnit.MILLISECONDS,
							t));
	if (fallback != null) {
		toReturn = toReturn.onErrorResume(fallback);
	}
	return toReturn;
}
 

@Test
public void testDecorateCheckedSupplier() throws IOException {
    given(helloWorldService.returnHelloWorldWithException()).willReturn("Hello world");
    CircuitBreaker circuitBreaker = CircuitBreaker.ofDefaults("helloBackend");
    CheckedFunction0<String> decoratedSupplier = Decorators
        .ofCheckedSupplier(() -> helloWorldService.returnHelloWorldWithException())
        .withCircuitBreaker(circuitBreaker)
        .withRetry(Retry.ofDefaults("id"))
        .withRateLimiter(RateLimiter.ofDefaults("testName"))
        .withBulkhead(Bulkhead.ofDefaults("testName"))
        .decorate();

    String result = Try.of(decoratedSupplier).get();

    assertThat(result).isEqualTo("Hello world");
    CircuitBreaker.Metrics metrics = circuitBreaker.getMetrics();
    assertThat(metrics.getNumberOfBufferedCalls()).isEqualTo(1);
    assertThat(metrics.getNumberOfSuccessfulCalls()).isEqualTo(1);
    then(helloWorldService).should(times(1)).returnHelloWorldWithException();
}
 

@Test
public void testDecorateSupplierWithFallback() {
    CircuitBreaker circuitBreaker = CircuitBreaker.ofDefaults("helloBackend");
    circuitBreaker.transitionToOpenState();

    Supplier<String> decoratedSupplier = Decorators
        .ofSupplier(() -> helloWorldService.returnHelloWorld())
        .withCircuitBreaker(circuitBreaker)
        .withFallback(asList(IOException.class, CallNotPermittedException.class), (e) -> "Fallback")
        .decorate();

    String result = decoratedSupplier.get();

    assertThat(result).isEqualTo("Fallback");
    CircuitBreaker.Metrics metrics = circuitBreaker.getMetrics();
    assertThat(metrics.getNumberOfNotPermittedCalls()).isEqualTo(1);
    then(helloWorldService).should(never()).returnHelloWorld();
}
 

@Test
public void testWithCircuitBreakerMetricsPublisher() throws Exception {
    CircuitBreakerConfig config =
        CircuitBreakerConfig.custom()
            .waitDurationInOpenState(Duration.ofSeconds(1))
            .failureRateThreshold(50)
            .permittedNumberOfCallsInHalfOpenState(3)
            .slidingWindowSize(10)
            .build();
    MetricRegistry metricRegistry = new MetricRegistry();
    CircuitBreakerRegistry circuitBreakerRegistry = CircuitBreakerRegistry
        .of(config, new CircuitBreakerMetricsPublisher(metricRegistry));
    CircuitBreaker circuitBreaker = circuitBreakerRegistry.circuitBreaker("test", config);

    circuitBreakerMetricsUsesFirstStateObjectInstance(circuitBreaker, metricRegistry);
}
 

@Test
public void testWithCircuitBreaker() throws Throwable {
    final CircuitBreaker circuitBreaker = CircuitBreaker.ofDefaults("test");
    final CircuitBreaker.Metrics metrics = circuitBreaker.getMetrics();
    final FeignDecorators testSubject = FeignDecorators.builder()
        .withCircuitBreaker(circuitBreaker).build();

    final Object result = testSubject.decorate(args -> args[0], null, null, null)
        .apply(new Object[]{"test01"});

    assertThat(result)
        .describedAs("Returned result is correct")
        .isEqualTo("test01");
    assertThat(metrics.getNumberOfSuccessfulCalls())
        .describedAs("Successful Calls")
        .isEqualTo(1);
}
 

@Test
public void testDecorateSupplier() {
    given(helloWorldService.returnHelloWorld()).willReturn("Hello world");
    CircuitBreaker circuitBreaker = CircuitBreaker.ofDefaults("helloBackend");
    Supplier<String> decoratedSupplier = Decorators
        .ofSupplier(() -> helloWorldService.returnHelloWorld())
        .withCircuitBreaker(circuitBreaker)
        .withRetry(Retry.ofDefaults("id"))
        .withRateLimiter(RateLimiter.ofDefaults("testName"))
        .withBulkhead(Bulkhead.ofDefaults("testName"))
        .decorate();

    String result = decoratedSupplier.get();

    assertThat(result).isEqualTo("Hello world");
    CircuitBreaker.Metrics metrics = circuitBreaker.getMetrics();
    assertThat(metrics.getNumberOfBufferedCalls()).isEqualTo(1);
    assertThat(metrics.getNumberOfSuccessfulCalls()).isEqualTo(1);
    then(helloWorldService).should(times(1)).returnHelloWorld();
}
 

@Test
public void shouldDelegateToOtherAdapter() {
    String body = "this is from rxjava";

    stubFor(get(urlPathEqualTo("/delegated"))
        .willReturn(aResponse()
            .withStatus(200)
            .withHeader("Content-Type", "text/plain")
            .withBody(body)));

    RetrofitService service = new Retrofit.Builder()
        .addCallAdapterFactory(CircuitBreakerCallAdapter.of(circuitBreaker))
        .addCallAdapterFactory(RxJava2CallAdapterFactory.create())
        .addConverterFactory(ScalarsConverterFactory.create())
        .baseUrl(wireMockRule.baseUrl())
        .client(client)
        .build()
        .create(RetrofitService.class);

    String resultBody = service.delegated().blockingGet();
    assertThat(resultBody).isEqualTo(body);
    verify(1, getRequestedFor(urlPathEqualTo("/delegated")));

    final CircuitBreaker.Metrics metrics = circuitBreaker.getMetrics();
    assertThat(metrics.getNumberOfSuccessfulCalls()).isEqualTo(1);
}
 

@Test
public void testWithCircuitBreakerMetrics() throws Exception {
    CircuitBreakerConfig config =
        CircuitBreakerConfig.custom()
            .waitDurationInOpenState(Duration.ofMillis(150))
            .failureRateThreshold(50)
            .permittedNumberOfCallsInHalfOpenState(3)
            .slidingWindowSize(10)
            .build();
    CircuitBreaker circuitBreaker = CircuitBreakerRegistry.ofDefaults()
        .circuitBreaker("test", config);
    MetricRegistry metricRegistry = new MetricRegistry();

    metricRegistry.registerAll(CircuitBreakerMetrics.ofCircuitBreaker(circuitBreaker));
    circuitBreakerMetricsUsesFirstStateObjectInstance(circuitBreaker, metricRegistry);
}
 

@Test
public void testDecorateCallable() throws Exception {
    given(helloWorldService.returnHelloWorldWithException()).willReturn("Hello world");
    CircuitBreaker circuitBreaker = CircuitBreaker.ofDefaults("helloBackend");
    Callable<String> decoratedCallable = Decorators
        .ofCallable(() -> helloWorldService.returnHelloWorldWithException())
        .withCircuitBreaker(circuitBreaker)
        .withRetry(Retry.ofDefaults("id"))
        .withRateLimiter(RateLimiter.ofDefaults("testName"))
        .withBulkhead(Bulkhead.ofDefaults("testName"))
        .decorate();

    String result = decoratedCallable.call();

    assertThat(result).isEqualTo("Hello world");
    CircuitBreaker.Metrics metrics = circuitBreaker.getMetrics();
    assertThat(metrics.getNumberOfBufferedCalls()).isEqualTo(1);
    assertThat(metrics.getNumberOfSuccessfulCalls()).isEqualTo(1);
    then(helloWorldService).should(times(1)).returnHelloWorldWithException();
}
 

@Test
public void shouldReportNewlyAddedCircuitBreaker() {
    String name = "newBackend";
    assertThat(registry.getSampleValue(
        DEFAULT_CIRCUIT_BREAKER_STATE,
        new String[]{"name", "state"},
        new String[]{name, circuitBreaker.getState().name().toLowerCase()}
    )).isNull();

    CircuitBreaker newlyAddedCircuitBreaker = circuitBreakerRegistry.circuitBreaker(name);

    double state = registry.getSampleValue(
        DEFAULT_CIRCUIT_BREAKER_STATE,
        new String[]{"name", "state"},
        new String[]{name, newlyAddedCircuitBreaker.getState().name().toLowerCase()}
    );

    assertThat(state).isEqualTo(1);
}
 

@Test
public void shouldAddMetricsForANewlyCreatedCircuitBreaker() {
    CircuitBreaker newCircuitBreaker = circuitBreakerRegistry.circuitBreaker("backendB");
    newCircuitBreaker.onSuccess(0, TimeUnit.NANOSECONDS);

    assertThat(taggedCircuitBreakerMetrics.meterIdMap).containsKeys("backendA", "backendB");
    assertThat(taggedCircuitBreakerMetrics.meterIdMap.get("backendA")).hasSize(16);
    assertThat(taggedCircuitBreakerMetrics.meterIdMap.get("backendB")).hasSize(16);

    List<Meter> meters = meterRegistry.getMeters();
    assertThat(meters).hasSize(32);

    Collection<Gauge> gauges = meterRegistry.get(DEFAULT_CIRCUIT_BREAKER_BUFFERED_CALLS)
        .gauges();

    Optional<Gauge> successful = MetricsTestHelper
        .findMeterByKindAndNameTags(gauges, "successful",
        newCircuitBreaker.getName());
    assertThat(successful).isPresent();
    assertThat(successful.get().value())
        .isEqualTo(newCircuitBreaker.getMetrics().getNumberOfSuccessfulCalls());
}
 

@Test
public void testDecorateCompletionStageWithCallNotPermittedExceptionFallback() throws ExecutionException, InterruptedException {
    CircuitBreaker circuitBreaker = CircuitBreaker.ofDefaults("helloBackend");
    circuitBreaker.transitionToOpenState();
    ThreadPoolBulkhead bulkhead = ThreadPoolBulkhead.ofDefaults("helloBackend");
    CompletionStage<String> completionStage = Decorators
        .ofSupplier(() -> helloWorldService.returnHelloWorld())
        .withThreadPoolBulkhead(bulkhead)
        .withCircuitBreaker(circuitBreaker)
        .withFallback(CallNotPermittedException.class, (e) -> "Fallback")
        .get();

    String result = completionStage.toCompletableFuture().get();

    assertThat(result).isEqualTo("Fallback");
    CircuitBreaker.Metrics metrics = circuitBreaker.getMetrics();
    assertThat(metrics.getNumberOfNotPermittedCalls()).isEqualTo(1);
}
 

@Test
public void testDecorateSupplierWithThreadPoolBulkhead()
    throws ExecutionException, InterruptedException {

    given(helloWorldService.returnHelloWorld()).willReturn("Hello world");
    CircuitBreaker circuitBreaker = CircuitBreaker.ofDefaults("helloBackend");

    CompletableFuture<String> future = Decorators
        .ofSupplier(() -> helloWorldService.returnHelloWorld())
        .withThreadPoolBulkhead(ThreadPoolBulkhead.ofDefaults("helloBackend"))
        .withTimeLimiter(TimeLimiter.ofDefaults(), Executors.newSingleThreadScheduledExecutor())
        .withCircuitBreaker(circuitBreaker)
        .get().toCompletableFuture();

    String result = future.get();

    assertThat(result).isEqualTo("Hello world");
    CircuitBreaker.Metrics metrics = circuitBreaker.getMetrics();
    assertThat(metrics.getNumberOfBufferedCalls()).isEqualTo(1);
    assertThat(metrics.getNumberOfSuccessfulCalls()).isEqualTo(1);
    then(helloWorldService).should(times(1)).returnHelloWorld();
}
 

@Test
public void testDecorateFunction() {
    given(helloWorldService.returnHelloWorldWithName("Name")).willReturn("Hello world Name");
    CircuitBreaker circuitBreaker = CircuitBreaker.ofDefaults("helloBackend");
    Function<String, String> decoratedFunction = Decorators
        .ofFunction(helloWorldService::returnHelloWorldWithName)
        .withCircuitBreaker(circuitBreaker)
        .withRetry(Retry.ofDefaults("id"))
        .withRateLimiter(RateLimiter.ofDefaults("testName"))
        .withBulkhead(Bulkhead.ofDefaults("testName"))
        .decorate();

    String result = decoratedFunction.apply("Name");

    assertThat(result).isEqualTo("Hello world Name");
    CircuitBreaker.Metrics metrics = circuitBreaker.getMetrics();
    assertThat(metrics.getNumberOfBufferedCalls()).isEqualTo(1);
    assertThat(metrics.getNumberOfSuccessfulCalls()).isEqualTo(1);
}
 

private static Health.Builder addDetails(Health.Builder builder,
                                         CircuitBreaker circuitBreaker) {
    CircuitBreaker.Metrics metrics = circuitBreaker.getMetrics();
    CircuitBreakerConfig config = circuitBreaker.getCircuitBreakerConfig();
    builder.withDetail(FAILURE_RATE, metrics.getFailureRate() + "%")
        .withDetail(FAILURE_RATE_THRESHOLD, config.getFailureRateThreshold() + "%")
        .withDetail(SLOW_CALL_RATE, metrics.getSlowCallRate() + "%")
        .withDetail(SLOW_CALL_RATE_THRESHOLD, config.getSlowCallRateThreshold() + "%")
        .withDetail(BUFFERED_CALLS, metrics.getNumberOfBufferedCalls())
        .withDetail(SLOW_CALLS, metrics.getNumberOfSlowCalls())
        .withDetail(SLOW_FAILED_CALLS, metrics.getNumberOfSlowFailedCalls())
        .withDetail(FAILED_CALLS, metrics.getNumberOfFailedCalls())
        .withDetail(NOT_PERMITTED, metrics.getNumberOfNotPermittedCalls())
        .withDetail(STATE, circuitBreaker.getState());
    return builder;
}
 

@Test
public void shouldBufferErrorEvents() {
    // tag::shouldBufferEvents[]
    CircuitBreaker circuitBreaker = CircuitBreaker.ofDefaults("testName");
    CircularEventConsumer<CircuitBreakerEvent> ringBuffer = new CircularEventConsumer<>(2);
    circuitBreaker.getEventPublisher().onEvent(ringBuffer);
    // end::shouldBufferEvents[]
    assertThat(ringBuffer.getBufferedEvents()).isEmpty();

    circuitBreaker.onError(0, TimeUnit.NANOSECONDS, new RuntimeException("Bla"));
    circuitBreaker.onError(0, TimeUnit.NANOSECONDS, new RuntimeException("Bla"));
    circuitBreaker.onError(0, TimeUnit.NANOSECONDS, new RuntimeException("Bla"));

    CircuitBreaker.Metrics metrics = circuitBreaker.getMetrics();
    assertThat(metrics.getNumberOfBufferedCalls()).isEqualTo(3);
    assertThat(metrics.getNumberOfFailedCalls()).isEqualTo(3);
    //Because capacity is 2
    assertThat(ringBuffer.getBufferedEvents()).hasSize(2);
}
 

@Test
public void testDecorateCheckedFunction() throws IOException {
    given(helloWorldService.returnHelloWorldWithNameWithException("Name"))
        .willReturn("Hello world Name");
    CircuitBreaker circuitBreaker = CircuitBreaker.ofDefaults("helloBackend");
    CheckedFunction1<String, String> decoratedFunction = Decorators
        .ofCheckedFunction(helloWorldService::returnHelloWorldWithNameWithException)
        .withCircuitBreaker(circuitBreaker)
        .withRetry(Retry.ofDefaults("id"))
        .withRateLimiter(RateLimiter.ofDefaults("testName"))
        .withBulkhead(Bulkhead.ofDefaults("testName"))
        .decorate();

    String result = Try.of(() -> decoratedFunction.apply("Name")).get();

    assertThat(result).isEqualTo("Hello world Name");
    CircuitBreaker.Metrics metrics = circuitBreaker.getMetrics();
    assertThat(metrics.getNumberOfBufferedCalls()).isEqualTo(1);
    assertThat(metrics.getNumberOfSuccessfulCalls()).isEqualTo(1);
}
 

@Test
public void testExecuteConsumer() {
    CircuitBreaker circuitBreaker = CircuitBreaker.ofDefaults("helloBackend");
    Decorators.DecorateConsumer<String> decoratedConsumer =
        Decorators.ofConsumer((String input) -> helloWorldService
            .sayHelloWorldWithName(input))
            .withCircuitBreaker(circuitBreaker)
            .withBulkhead(Bulkhead.ofDefaults("testName"))
            .withRateLimiter(RateLimiter.ofDefaults("testName"));

    decoratedConsumer.accept("test");

    CircuitBreaker.Metrics metrics = circuitBreaker.getMetrics();
    assertThat(metrics.getNumberOfBufferedCalls()).isEqualTo(1);
    assertThat(metrics.getNumberOfSuccessfulCalls()).isEqualTo(1);
    then(helloWorldService).should(times(1)).sayHelloWorldWithName("test");
}
 

@Test
public void shouldRecordIOExceptionAsFailureAndBusinessExceptionAsSuccess() {
    CircuitBreaker circuitBreaker = new CircuitBreakerStateMachine("testName", custom()
        .slidingWindowSize(5)
        .recordExceptions(IOException.class)
        .build());

    assertThat(circuitBreaker.tryAcquirePermission()).isEqualTo(true);
    circuitBreaker.onError(0, TimeUnit.NANOSECONDS, new IOException());

    // Call 2 is a failure
    assertThat(circuitBreaker.tryAcquirePermission()).isEqualTo(true);
    circuitBreaker.onError(0, TimeUnit.NANOSECONDS, new BusinessException("test"));

    assertThat(circuitBreaker.getMetrics().getNumberOfFailedCalls()).isEqualTo(1);
    assertThat(circuitBreaker.getMetrics().getNumberOfSuccessfulCalls()).isEqualTo(1);
    assertThat(circuitBreaker.getMetrics().getNumberOfBufferedCalls()).isEqualTo(2);
}
 

@Test
public void shouldIgnoreNumberFormatException() {
    CircuitBreaker circuitBreaker = new CircuitBreakerStateMachine("testName", custom()
        .failureRateThreshold(50)
        .slidingWindowSize(5)
        .waitDurationInOpenState(Duration.ofSeconds(5))
        .ignoreExceptions(NumberFormatException.class)
        .build());

    assertThat(circuitBreaker.tryAcquirePermission()).isEqualTo(true);
    circuitBreaker.onError(0, TimeUnit.NANOSECONDS, new RuntimeException());

    // Call 2 is a failure
    assertThat(circuitBreaker.tryAcquirePermission()).isEqualTo(true);
    circuitBreaker.onError(0, TimeUnit.NANOSECONDS, new NumberFormatException());

    assertThat(circuitBreaker.getMetrics().getNumberOfFailedCalls()).isEqualTo(1);
    assertThat(circuitBreaker.getMetrics().getNumberOfSuccessfulCalls()).isEqualTo(0);
    assertThat(circuitBreaker.getMetrics().getNumberOfBufferedCalls()).isEqualTo(1);
}
 

@Test
public void shouldRegisterMetrics() {
    CircuitBreaker circuitBreaker = givenMetricRegistry(metricRegistry);
    given(helloWorldService.returnHelloWorld()).willReturn("Hello world");

    String value = circuitBreaker.executeSupplier(helloWorldService::returnHelloWorld);

    assertThat(value).isEqualTo("Hello world");
    then(helloWorldService).should(times(1)).returnHelloWorld();
    assertThat(metricRegistry.getMetrics()).hasSize(10);
    assertThat(
        metricRegistry.getGauges().get("resilience4j.circuitbreaker.testName.state").getValue())
        .isEqualTo(0);
    assertThat(metricRegistry.getGauges().get("resilience4j.circuitbreaker.testName.buffered")
        .getValue()).isEqualTo(1);
    assertThat(metricRegistry.getGauges().get("resilience4j.circuitbreaker.testName.successful")
        .getValue()).isEqualTo(1);
    assertThat(metricRegistry.getGauges().get("resilience4j.circuitbreaker.testName.failed")
        .getValue()).isEqualTo(0);
    assertThat(
        metricRegistry.getGauges().get("resilience4j.circuitbreaker.testName.slow").getValue())
        .isEqualTo(0);
    assertThat(
        metricRegistry.getGauges().get("resilience4j.circuitbreaker.testName.slow_successful")
            .getValue()).isEqualTo(0);
    assertThat(
        metricRegistry.getGauges().get("resilience4j.circuitbreaker.testName.slow_failed")
            .getValue()).isEqualTo(0);
    assertThat(
        metricRegistry.getGauges().get("resilience4j.circuitbreaker.testName.not_permitted")
            .getValue()).isEqualTo(0L);
    assertThat(
        metricRegistry.getGauges().get("resilience4j.circuitbreaker.testName.failure_rate")
            .getValue()).isEqualTo(-1f);
    assertThat(
        metricRegistry.getGauges().get("resilience4j.circuitbreaker.testName.slow_call_rate")
            .getValue()).isEqualTo(-1f);
}
 

public Method findFallbackMethodInternal(Method method, Class<?> targetClass,
                                         Class<? extends Throwable> throwableClass,
                                         com.baidu.formula.circuitbreaker.annotation.CircuitBreaker annotation) {
    for (; throwableClass != null && Throwable.class.isAssignableFrom(throwableClass);
         throwableClass = (Class<? extends Throwable>) throwableClass.getSuperclass()) {
        Class<?>[] parameterTypes = Stream.concat(
                Arrays.stream(method.getParameterTypes()),
                Stream.of(throwableClass)).toArray(Class<?>[]::new);
        Method fallbackMethod = ReflectionUtils.findMethod(targetClass, annotation.fallback(), parameterTypes);

        if (fallbackMethod != null) {
            return fallbackMethod;
        }

        Class<?>[] interfaces = Arrays.stream(throwableClass.getInterfaces())
                .filter(Throwable.class::isAssignableFrom)
                .toArray(Class[]::new);
        for (Class<?> i : interfaces) {
            parameterTypes = Stream.concat(
                    Arrays.stream(method.getParameterTypes()),
                    Stream.of(i)).toArray(Class<?>[]::new);
            fallbackMethod = ReflectionUtils.findMethod(targetClass, annotation.fallback(), parameterTypes);
            if (fallbackMethod != null) {
                return fallbackMethod;
            }
        }
    }

    return ReflectionUtils.findMethod(targetClass, annotation.fallback(), method.getParameterTypes());
}
 

@Bean
@Primary
public RegistryEventConsumer<CircuitBreaker> circuitBreakerRegistryEventConsumer(
    Optional<List<RegistryEventConsumer<CircuitBreaker>>> optionalRegistryEventConsumers) {
    return circuitBreakerConfiguration
        .circuitBreakerRegistryEventConsumer(optionalRegistryEventConsumers);
}
 

@Override
public void bindTo(MeterRegistry registry) {
    for (CircuitBreaker circuitBreaker : circuitBreakerRegistry.getAllCircuitBreakers()) {
        addMetrics(registry, circuitBreaker);
    }
    circuitBreakerRegistry.getEventPublisher()
        .onEntryAdded(event -> addMetrics(registry, event.getAddedEntry()));
    circuitBreakerRegistry.getEventPublisher()
        .onEntryRemoved(event -> removeMetrics(registry, event.getRemovedEntry().getName()));
    circuitBreakerRegistry.getEventPublisher().onEntryReplaced(event -> {
        removeMetrics(registry, event.getOldEntry().getName());
        addMetrics(registry, event.getNewEntry());
    });
}
 

@Test
public void telemetryDownEchoStillHealthyTest() throws Exception {
  mockMvc.perform(get("/health")).andExpect(status().isOk());

  // Simulate the stats endpoint going down, tripping the circuit breaker.
  CircuitBreaker cb =
      circuitBreakerRegistry.circuitBreaker(TelemetryEventListener.TELEMETRY_REGISTRY_NAME);
  cb.transitionToOpenState();

  mockMvc.perform(get("/health")).andExpect(status().isOk());
}
 

public <T> T handle(BackendService<T> backendService) {

        if (this.circuitBreakerConfig == null) {
            this.circuitBreakerConfig = circuitBreakerRegistry.getConfiguration(circuitBreakerL2cacheName)
                    .orElse(circuitBreakerRegistry.getDefaultConfig());
        }
        CircuitBreaker circuitBreaker = circuitBreakerRegistry.circuitBreaker(circuitBreakerL2cacheName,this.circuitBreakerConfig);
        Supplier<T> decoratedSupplier = CircuitBreaker
                .decorateSupplier(circuitBreaker, backendService::handle);
        if (fallbackStorage == null)
            return Try.ofSupplier(decoratedSupplier).get();
        return Try.ofSupplier(decoratedSupplier).recover(e -> handleException(e,backendService)).get();
    }